Department of General and Experimental Pathology, University of Graz, A-8010 Graz, Austria
cDepartment of Anatomy, Medical School Hannover, D-30623 Hannover, Germany
dDepartment of Biochemistry and Molecular Biology, College of Medicine, University of Illinois, Chicago, Illinois 60612, USA
Our work is devoted to defining relationships between the immune
system and the adrenergic and cholinergic systems
in vivo. In
the rat model, we have shown that the cells of different immune
compartments express the genes of a defined set of adrenergic/cholinergic
receptors, and it was shown that lymphocytes are a site of non-neuronal
production of norepinephrine and acetylcholine. Furthermore,
using implantable slow-release tablets containing adrenergic
or cholinergic agonists/antagonists, distinct and partly opposite
effects were observed on peripheral immune functions. Concerning
sympathetic immunoregulation, our data-in contrast to those
of other studies-suggest that an enhanced adrenergic tonus leads
to immunosuppression primarily via
2-receptor-mediated mechanisms.
Beta-blockade strongly enhances this effect, most likely by
inhibition of pineal melatonin synthesis. In recent experiments
on the kinetics it was found that the continuous
-adrenergic
treatment entails a strong suppression of cellular responsiveness
during the first few hours, which is increasingly followed by
a general loss of lymphocytes in blood and lymphoid organs most
likely due to enhanced apoptosis. More recently, we have extended
our studies to the mouse model. First data obtained with RNAse
protection assays suggest a biphasic effect on the gene expression
of several cytokines in spleen cells due to adrenergic
in vivo treatment.
